'London Assurance' Summary

Charles and Dazzle arrive at Sir Harcourt's London home after a night on the town and manage to avoid Harcourt with Cool's help; Harcourt still believes that Charles is a clean-living innocent. Max arrives to make the final arrangements for Harcourt's marriage to Max's niece Grace. Max has made Grace's inheritance contingent on her marrying Harcourt; if she does not, it will pass to Charles. In return, Harcourt has financially helped him. Harcourt leaves and Dazzle bumps into Max, gaining himself an invitation to Oak Hall in Gloucestershire, Max's country house, and Charles will accompany him on the trip.

At Oak Hall, Grace tells her maid Pert about her acceptance of marriage to the aged Sir Harcourt and explains her view of love as an "epidemic madness". Charles and Dazzle arrive; Charles does not know of his father's marriage plans and immediately starts courting Grace. Harcourt arrives and Charles tells him that he is actually named Augustus Hamilton and merely bears a remarkable likeness to Charles. His father is convinced for a time.

Lady Gay Spanker and her husband "Dolly" arrive, and Sir Harcourt immediately falls in love with the former. Grace begins to fall in love with Charles/Augustus in spite of herself. When Lady Gay interrupts their courtship, Charles easily persuades the lady to distract Sir Harcourt from marriage to Grace by apparently accepting his affections. Charles leaves as 'Augustus', returning as Charles to tell Grace that 'Augustus' has been killed, to see if she really loves him, whilst Lady Gay and Sir Harcourt plan to elope.

The elopement is frustrated by Max, Dolly and the local lawyer Meddle. Dolly challenges Sir Harcourt to a duel. Sir Harcourt realises he has been duped and resolves to release Grace from their marriage contract.

Max prevents the duel and Grace insists on going through with the marriage to Sir Harcourt, as a ruse to force Charles's hand. Charles's creditors catch up with him. Dolly forgives Gay and Sir Harcourt finds out his son's true nature as well as acceding to Charles's marriage to Grace.